In conventional magnetic recording media, a high quality has been tried to provide by making magnetic powder fine in one case, or by arranging a multilayered structure in which a magnetic layer is arranged to the upper layer and a non-magnetic layer, to the lower layer, respectively, in the other case. Refer to Japanese Patent Application Open to Public Inspection (hereinafter referred to as JP OPI Publication) No. 63-187418/1988.
In the former case, however, magnetic powder only is made fine and, in the latter case of JP OPI Publication No. 63-187418/1988, the dispersibility of magnetic or non-magnetic powder is inferior in a coating material for forming a magnetic or non-magnetic layer, because the configuration of the non-magnetic powder is inappropriate, and a calenderability is deteriorated in a calendering treatment, so that the surface property of a magnetic recording medium cannot be resulted in a satisfactory condition. It has, therefore, been difficult to obtain a magnetic recording medium excellent in electric property and running property required for serving as a digital recording medium.
Generally in a multilayered magnetic recording medium, the surface property of the uppermost layer is seriously affected by the surface property of the layer adjacent lower to the uppermost layer. This tendency becomes more apparent as the thickness of the uppermost magnetic layer is getting more thinner.
Therefore, for improving the surface property of the uppermost magnetic layer, it is required to improve the surface property of the layer adjacent lower to the uppermost layer. For satisfying the requirement, it is effective to make fine a powder applied to the layer adjacent lower to the uppermost layer so that the dispersibility of the powder can be improved by making use of a binder containing a polar group. Refer to JP OPI Publication No. 4-57217/1992. However, as the powder applicable to the lower layer is made fine, the physical properties such as Young's modulus are deteriorated so as to raise such a problem that a running property at a low temperature and a head-touch property, or an envelope property, are deteriorated. The problem is getting more serious as a tape is made more thinner for making it longer in length.